What's the prognosis for pleural plaques?
Q - A patient with a history of asbestos exposure in a power station has been found to have pleural plaques in a CXR. What is the prognosis of this finding alone? What is her risk of fibrosis and mesothelioma?
A - There is no prognostic value in pleural plaques by themselves. Pleural plaques are circumscribed areas of hyaline fibrous tissue on the surface of the pleura and develop in direct response to presence of fibres. They are seen in characteristic locations on chest X-ray although conventional radiography detects less than half of all pleural plaques and high resolution CT will find many more. While plaques are found incidentally in the general population they are far more common in those exposed to fibrous materials such as asbestos but also other material such as erionite (environmentally) and possibly from ceramic fibres.
Studies have found plaque prevalence of more than 50 per cent in some occupational groups exposed to asbestos. They are benign asbestos pleural disease, not associated with symptoms or altered lung function unless there is accompanying interstitial fibrosis. Crackles may be heard if the plaques become benign pleural thickening. They do not qualify for prescribed disease status or for industrial injuries benefit.
The risk of fibrosis and mesothelioma in this patient relates to her history of asbestos exposure, not to the presence of pleural plaques.
In general she should be reassured and advised that there is no need for follow-up.
Unless she has been lagging, stripping or carrying out construction work which involves grinding or cutting asbestos there should be insignificant risk of other asbestos disease.
John Hobson, consultant occupational physician,
MPCG Ltd, Staffordshire